On 29 November 2011 Siemens Energy launched its new 6-megawatt (MW) direct drive wind turbine at the European Offshore Wind Energy Conference in Amsterdam, The Netherlands. The new SWT-6.0 will be available with rotor diameters of 120 and 154 meters and is designed for the most challenging offshore sites. It features the Siemens direct drive design with 50 per cent fewer parts than comparable geared wind turbines. With a towerhead mass of roughly 350 tons, the SWT-6.0 is the lightest machine in its class. This unique combination of robustness and low weight significantly reduces infrastructure, installation and service costs, and boosts lifetime energy output and profitability.

The prototype of the new 6.0 MW direct drive wind turbine. The SWT-6.0 will be available with rotor diameters of 120 and 154 meters and is designed for the most challenging offshore sites. With a towerhead weighing about 350 tons, the SWT-6.0 is the lightest machine in its class. (click image to expand - image courtesy of Siemens)

“Our new 6-megawatt offshore wind turbine incorporates the aggregate engineering know-how gained through the last three decades. We expect the SWT-6.0 turbine to become the new standard for offshore wind power projects around the globe. With its smart design and low weight, the SWT-6.0 will contribute significantly to the reduction of the cost of energy for offshore wind power”, said Henrik Stiesdal, Chief Technology Officer of the Siemens Wind Power Division.

Siemens is the most experienced player in the offshore wind power sector. The company pioneered the industry when it installed the world’s first offshore wind power plant in 1991. Since then, Siemens has successfully installed more than 700 offshore wind turbines with a combined capacity of more than 2,000 MW in European waters. In offshore wind power alone, Siemens has an order backlog of more than 1,100 offshore wind turbines with a total capacity of more than 4,000 MW.

The new Siemens 6-MW wind turbine is purpose-built to endure the harshest conditions offshore. This direct drive wind turbine is offered with two different rotor blades.

The SWT-6.0-154 features the largest rotor blade in the 6-MW class, using the new B75 Quantum Blade. This 75 meter long blade delivers enormous strength at low weight, and thanks to its unique airfoils the B75 Quantum Blade offers superior performance at a wide range of wind speeds.

The SWT-6.0-120 is equipped with the proven B58 rotor blade. This 58 meter long blade is known from the world’s bestselling offshore wind turbine, SWT-3.6-120. The SWT-6.0-120 will bring direct drive technology to customers offshore, even in areas where air traffic and height restrictions ordinarily preclude wind turbine installations of the 6-MW class.

The SWT 6.0 is designed to increase the speed of offshore installations to bring down the cost of energy. The entire electrical system of the new 6-MW machine – including the medium voltage system and the full converter – is now enclosed in the nacelle. Thus, pre-commissioning testing can be achieved onshore faster and more safely. Furthermore, commissioning will be speeded up significantly, too.

The SWT-6.0 is designed to offer a safe working environment. A helicopter-hoisting platform is integrated in the nacelle rear and allows easy and safe access for service technicians. The nacelle, housing far fewer parts than geared wind turbines, is particularly spacious and gives technicians easy access to key components.

The first prototype of the Siemens 6-megawatt turbine was installed in May, 2011 at Høvsøre, Denmark. Siemens is currently in the process of thoroughly testing and validating the performance of the turbine. “The testing has confirmed our calculations”, said CTO Henrik Stiesdal. In addition to prototype testing, Siemens runs every component through a simulated 25 years of our highly accelerated lifetime testing (HALT). A pre-series of up to 50 SWT-6.0 wind turbines will be installed at on- and offshore sites in Denmark, Germany, The Netherlands and in the UK during 2012 and 2013.

Wind Power is part of Siemens’ Environmental Portfolio. In fiscal 2011, revenue from the Portfolio totaled about €30 billion, making Siemens one of the world’s largest suppliers of ecofriendly technologies.

In the same period, our products and solutions enabled customers to reduce their carbon dioxide (CO2) emissions by nearly 320 million tons, an amount equal to the total annual CO2 emissions of Berlin, Delhi, Hong Kong, Istanbul, London, New York, Singapore and Tokyo.